Salicylic acid, also known as 2-hydroxybenzenecarboxylic acid, is a monohydroxybenzoic acid. Its salts and esters are known as salicylates. Salicylic acid has the formula:

Salicylic acid is also known for providing pain relief when applied as a liniment, for example
Salicylic acid is used in many skin-care products. For example, salicylic acid is well known for its use in anti-acne treatments. In addition to the treatment of acne, salicylic acid is also used in products for treatment of psoriasis, calluses, corns, keratosis pilaris, and warts. It works as a keratolytic, bacteriocide and comedolytic agent. Salicylic acid is also used in shampoos for treatment of dandruff and as a chemical exfoliant.
Salicylic acid can cause burns if applied in high concentrations. Typically, over-the-counter limits are 2% for topical treatments (that remain on the skin) and 3% for cleansers or shampoo (products that are washed off.) Higher concentrations (e.g. up to 40 wt %) may be used for wart removal but should be applied cautiously and only to the wart and not the surrounding skin.
Salicylic acid is poorly soluble in water. It is therefore difficult to prepare solutions of salicylic acid that remain precipitate-free.